fix(tools): preserve MCP server-side tool name after rename - #1612
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ajbozarth merged 1 commit intoSep 3, 2026
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MCPToolSpec.as_mellea_tool passed the user-editable `name` field as both the model-facing tool name and the name sent to the MCP server in call_tool(). Reassigning `name` to disambiguate tools that collide across multiple servers therefore broke the actual invocation, because the server only knows the original name. Preserve the original server-side name at construction and use it for the tool call, leaving `name` free for model-facing disambiguation. This makes the rename workaround noted when closing generative-computing#1594 actually work. Fixes generative-computing#1594 Assisted-by: Claude Code Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>
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Issue
Fixes #1594
Description
When #1594 was closed, the noted workaround was to reassign
MCPToolSpec.name(and.description) before callingas_mellea_tool()to disambiguate tools that share a name across multiple MCP servers. That workaround was silently broken:as_mellea_tool()usedself.nameboth for the model-facing tool name and for the name sent to the server incall_tool(). A reassigned.namewas therefore sent to the server, which only knows the original name, so the invocation failed.This preserves the original server-side name at construction (
_server_tool_name) and uses it for the actual tool invocation, leaving.namefree for model-facing disambiguation. Adds a regression test and documents the supported reassignment behavior in theMCPToolSpecdocstring.Spun off from the design discussion on #1432, which resolved the tool-name-collision cases for component tools. That PR intentionally left user-supplied tools out of scope, on the basis that a user can rename their own function to avoid a conflict. MCP tools are the corner of that case: they are user-supplied, but their names come from the server rather than the user — so "rename it yourself" (reassigning
MCPToolSpec.name, as noted on #1594) was the intended escape hatch. This PR makes that escape hatch actually work, by keeping the server-side name distinct from the reassignable model-facing name.Testing
Attribution
Adding a new component, requirement, sampling strategy, or tool?
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